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Contrast normalization and a linear model for the directional selectivity of simple cells in cat striate cortex

Published online by Cambridge University Press:  02 June 2009

D.J. Tolhurst
Affiliation:
The Physiological Laboratory, Downing Street, Cambridge, UK
D.J. Heeger
Affiliation:
Department of Psychology, Stanford University, Stanford, CA

Abstract

Previous tests of the linearity of spatiotemporal summation in cat simple cells have compared the responses to moving sinusoidal gratings and to gratings whose contrast was modulated sinusoidally in time. In particular, since a moving grating can be expressed as a sum of modulated gratings, the response to a moving grating should be predictable (assuming linearity) from the responses to modulated gratings. However, these simple linear predictions have shown varying degrees of failure (e.g. Reid et al., 1987, 1991), depending on the directional selectivity of the neurons (Tolhurst & Dean, 1991). We demonstrate here that the failures of these linear predictions are, in fact, explained by the contrast-normalization model of Heeger (1993). We concentrate on the ratio of the measured to predicted moving grating responses. In the context of the contrast-normalization model, calculating this ratio turns out to be particularly appropriate, since the ratio is independent of the precise details of the linear front-end mechanisms ultimately responsible for directional selectivity. Hence, the contrast-normalization model can be compared quantitatively with this ratio measure, by varying only one free parameter. When account is taken both of the expansive output nonlinearity and of contrast normalization, the directional selectivity of simple cells seems to be dependent only on linear spatiotemporal filtering.

Type
Research Articles
Copyright
Copyright © Cambridge University Press 1997

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References

Adelson, E.H. & Bergen, J.R. (1985). Spatiotemporal energy models for the perception of motion. Journal of the Optical Society of America A 2, 284299.CrossRefGoogle ScholarPubMed
Albrecht, D.G. & Geisler, W.S. (1991). Motion selectivity and the contrast-response function of simple cells in the visual cortex. Visual Neuroscience 7, 531546.CrossRefGoogle ScholarPubMed
Albrecht, D.G. & Hamilton, D.B. (1982). Striate cortex of monkey and cat: Contrast response function. Journal of Neurophysiology 48, 217237.CrossRefGoogle ScholarPubMed
Barlow, H.B. & Levick, W.R. (1965). The mechanism of directionally selective units in rabbit's retina. Journal of Physiology 178, 477504.CrossRefGoogle ScholarPubMed
Burr, D.C., Ross, J. & Morrone, M.C. (1986). Seeing objects in motion. Proceedings of the Royal Society B 227, 249265.Google ScholarPubMed
Dean, A.F., Hess, R.F. & Tolhurst, D.J. (1980). Divisive inhibition involved in directional selectivity. Journal of Physiology 308, 8485P.Google Scholar
Dean, A.F. & Tolhurst, D.J. (1983). On the distinctness of simple and complex cells in the visual cortex of the cat. Journal of Physiology 344, 305325.CrossRefGoogle ScholarPubMed
Dean, A.F. & Tolhurst, D.J. (1986). Factors influencing the temporal phase of response to bar and grating stimuli for simple cells in the cat striate cortex. Experimental Brain Research 62, 143151.CrossRefGoogle ScholarPubMed
DeAngelis, G.C., Ohzawa, I. & Freeman, R.D. (1993 a). Spatiotemporal organization of simple-cell receptive fields in the cat's striate cortex. I, General characteristics and postnatal development. Journal of Neurophysiology 69, 10911117.CrossRefGoogle ScholarPubMed
DeAngelis, G.C., Ohzawa, I. & Freeman, R.D. (1993 b). Spatiotemporal organization of simple-cell receptive fields in the cat's striate cortex. II, Linearity of temporal and spatial summation. Journal of Neurophysiology 69, 11181135.CrossRefGoogle ScholarPubMed
Emerson, R.C. (1996). Quadrature subunits in directionally selective simple cells: Spatiotemporal interactions. Visual Neuroscience (in press).Google Scholar
Emerson, R.C. & Citron, M.C. (1992). Linear and nonlinear mechanisms of motion selectivity in single cells of the cat's striate cortex. In Nonlinear Vision: Determination of Neural Receptive Fields, Function, and Networks, ed. Pinter, R.B. & Nabet, B. pp. 7589. Boca Raton, Florida: CRC Press.Google Scholar
Emerson, R.C. & Gerstein, G.L. (1977). Simple striate neurons in the cat. II, Mechanisms underlying directional asymmetry and directional selectivity. Journal of Neurophysiology 40, 136155.CrossRefGoogle ScholarPubMed
Emerson, R.C. & Huang, M.C. (1996). Quadrature subunits in directionally selective simple cells: Counterphase and drifting grating responses. Visual Neuroscience (in press).Google Scholar
Fahle, M. & Poggio, T. (1981). Visual hyperacuity: Spatiotemporal interpolation in human vision. Proceedings of the Royal Society B 213, 451477.Google ScholarPubMed
Ganz, L. & Felder, R. (1984). Mechanism of directional selectivity in simple neurons of the cat's visual cortex analyzed with stationary flash sequences. Journal of Neurophysiology 51, 294324.CrossRefGoogle ScholarPubMed
Goodwin, A.W., Henry, G.H. & Bishop, P.O. (1975). Direction selectivity of simple striate cells: Properties and mechanism. Journal of Neurophysiology 38, 15001523.CrossRefGoogle ScholarPubMed
Heeger, D.J. (1991). Nonlinear model of neural responses in cat visual cortex. In: Computational Models of Visual Processing, ed. Landy, M. & Movshon, J.A., pp. 119133. Cambridge, Massachusetts: MIT Press.Google Scholar
Heeger, D.J. (1992). Half-squaring in responses of cat simple cells. Visual Neuroscience 9, 427443.CrossRefGoogle Scholar
Heeger, D.J. (1993). Modeling simple-cell direction selectivity with normalized, half-squared, linear operators. Journal of Neurophysiology 70, 18851898.CrossRefGoogle ScholarPubMed
Hubel, D.H. & Wiesel, T.N. (1959). Receptive fields of single neurones in the cat's striate cortex. Journal of Physiology 148, 574591.CrossRefGoogle ScholarPubMed
Ikeda, H. & Wright, M.J. (1974). Sensitivity of neurones in visual cortex (area 17) under different levels of anaesthesia. Experimental Brain Research 20, 471484.CrossRefGoogle ScholarPubMed
Jagadeesh, B., Wheat, H.S. & Ferster, D. (1993). Linearity of summation of synaptic potentials underlying direction selectivity in simple cells of the cat visual cortex. Science 262, 19011904.CrossRefGoogle ScholarPubMed
Kontsevich, L.L. (1995). The nature of the inputs to cortical motion detectors. Vision Research 35, 27852793.CrossRefGoogle ScholarPubMed
Maffei, L. & Fiorentini, A. (1973). The visual cortex as a spatial frequency analyzer. Vision Research 13, 12551267.CrossRefGoogle Scholar
McLean, J. & Palmer, L.A. (1989). Contribution of linear spatiotemporal receptive-field structure to velocity selectivity of simple cells in area 17 of the cat. Vision Research 29, 675679.CrossRefGoogle Scholar
McLean, J., Raab, S. & Palmer, L.A. (1994). Contribution of linear mechanisms to the specification of local motion by simple cells in areas 17 and 18 of the cat. Visual Neuroscience 11, 271294.CrossRefGoogle Scholar
Movshon, J.A., Thompson, I.D. & Tolhurst, D.J. (1978). Spatial summation in the receptive fields of simple cells in the cat's striate cortex. Journal of Physiology 283, 5377.CrossRefGoogle ScholarPubMed
Pettigrew, J.D., Nikara, T. & Bishop, P.O. (1968). Responses to moving slits by single units in cai striate cortex. Experimental Brain Research 6, 373390.CrossRefGoogle Scholar
Reid, R.C., Soodak, R.E. & Shapley, R.M. (1987). Linear mechanisms of directional selectivity in simple cells of cat striate cortex. Proceedings of the National Academy of Sciences of the U.S.A. 84, 87408744.CrossRefGoogle ScholarPubMed
Reid, R.C., Soodak, R.E. & Shapley, R.M. (1991). Directional selectivity and spatiotemporal structure of receptive fields of simple cells in cat striate cortex. Journal of Neurophysiology 66, 505529.CrossRefGoogle ScholarPubMed
Sillito, A.M. (1977). Inhibitory processes underlying the directional specificity of simple, complex, and hypercomplex cells in the cat's visual cortex. Journal of Physiology 271, 699720.CrossRefGoogle ScholarPubMed
Tolhurst, D.J. & Dean, A.F. (1987). Spatial summation by simple cells in the striate cortex of the cat. Experimental Brain Research 66, 607620.CrossRefGoogle ScholarPubMed
Tolhurst, D.J. & Dean, A.F. (1991). Evaluation of a linear model of directional selectivity in simple cells of the cat's striate cortex. Visual Neuroscience 6, 421428.CrossRefGoogle ScholarPubMed
Tolhurst, D.J. & Heeger, D.J. (1997). Contrast-normalization and hardthreshold models of the responses of simple cells in cat striate cortex. Visual Neuroscience 14 (in press).Google Scholar
Tolhurst, D.J., Movshon, J.A. & Thompson, I.D. (1981). The dependence of response amplitude and variance of cat visual cortical neurones on stimulus contrast. Experimental Brain Research 41, 414419.Google ScholarPubMed
van Santen, J.P.H. & Sperling, G. (1985). Elaborated Reichardt detectors. Journal of the Optical Society of America A 2, 300321.CrossRefGoogle ScholarPubMed
Watson, A.B. & Ahumada, A.J. (1983). A look at motion in the frequency domain. NASA Technical Memorandum 84352, 110.Google Scholar
Watson, A.B. & Ahumada, A.J. (1985). Model of human visual-motion sensing. Journal of the Optical Society of America A 2, 322342.CrossRefGoogle ScholarPubMed